I want to wake up and unlock a device. Then, I'd like show an activity when the user has new message from Firebase. 
I wrote this on onResume() method:
window = this.getWindow();
window.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED | WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
This works for devices with API > 19. The problem is that in KitKat, it either does nothing or it wakes up the screen but doesn't unlock the device.
Also I set the right permissions in the AndroidManifest.xml:
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.DISABLE_KEYGUARD" />
Also in MyFirebaseMessagingService.class, I'm starting an activity with FLAG_ACTIVITY_NEW_TASK as flag.
Does anyone know what am I missing?
Thanks for the help.